# Frequency Domain

NI Vision 2019 for LabVIEW Help

Edition Date: March 2019

Part Number: 370281AG-01

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Owning Palette: Image Processing
Requires: NI Vision Development Module

Use the Frequency Domain VIs to perform frequency processing and other tasks on images. Use these VIs to convert an image from the spatial domain to the frequency domain using a two-dimensional Fast Fourier Transform (FFT) and convert an image from the frequency domain to the spatial domain using the inverse FFT. These VIs also extract the magnitude, phase, real, and imaginary planes of the complex image.

Palette Object Description
IMAQ FFT

Computes the FFT of an image. The FFT creates a complex image in which high frequencies are grouped at the center, while low frequencies are located at the edges.

IMAQ InverseFFT

Computes the inverse FFT of a complex image.

IMAQ ArrayToComplexImage

Creates a complex image from a 2D array of complex numbers.

IMAQ ArrayToComplexPlane

Replaces the real part or the imaginary part of a complex image, starting from a 2D array of floating-point values.

IMAQ ImageToComplexPlane

Extracts the pixels from an 8-bit, 16-bit, 32-bit floating-point, or Complex image into the real part or imaginary part of a complex image.

IMAQ ComplexImageToArray

Extracts the pixels from a complex image into a complex 2D array.

IMAQ ComplexPlaneToArray

Extracts the pixels from the real part, imaginary part, magnitude, or phase of a complex image into a 2D array of floating-point numbers.

IMAQ ComplexPlaneToImage

Extracts the pixels from the real part, imaginary part, magnitude, or phase of a complex image into an 8-bit, 16-bit, or 32-bit floating-point image.

IMAQ ComplexConjugate

Computes the conjugate of a complex image. This VI converts the complex pixel data z = a + ib of a complex image into z = a &#150; ib.

IMAQ ComplexAttenuate

Attenuates the frequencies of a complex image.

Adds two images where the first is a complex image, or adds a complex image and a complex number.

IMAQ ComplexSubtract

Subtracts two images where the first is a complex image, or subtracts a complex number from a complex image.

IMAQ ComplexFlipFrequency

Transposes the frequency components of a complex image. The high and low frequency components of a complex image are inverted to produce a central symmetric representation of the spatial frequencies.

IMAQ ComplexTruncate

Truncates the frequencies of a complex image.

IMAQ ComplexMultiply

Multiplies two images where the first is a complex image, or multiples a complex image and a complex number.

IMAQ ComplexDivide

Divides one image by another where the first is a complex image, or divides a complex image by a complex number.